[PATCH] Kill get/put_cpu_ptr

[J.A. Magallon]

Someone asked for this in the list...
Against rc3-mm2, compiled and booted:

--- linux-2.6.9-rc3-mm2-cln/include/linux/percpu.h	2004-06-16 07:20:03.000000000 +0200
+++ linux-2.6.9-rc3-mm2/include/linux/percpu.h	2004-10-05 13:57:58.000000000 +0200
@@ -24,8 +24,7 @@

/* 
 * Use this to get to a cpu's version of the per-cpu object allocated using
- * alloc_percpu.  If you want to get "this cpu's version", maybe you want
- * to use get_cpu_ptr... 
+ * alloc_percpu.
 */ 
#define per_cpu_ptr(ptr, cpu)                   \
({                                              \
@@ -58,26 +57,4 @@
#define alloc_percpu(type) \
	((type *)(__alloc_percpu(sizeof(type), __alignof__(type))))

-/* 
- * Use these with alloc_percpu. If
- * 1. You want to operate on memory allocated by alloc_percpu (dereference
- *    and read/modify/write)  AND 
- * 2. You want "this cpu's version" of the object AND 
- * 3. You want to do this safely since:
- *    a. On multiprocessors, you don't want to switch between cpus after 
- *    you've read the current processor id due to preemption -- this would 
- *    take away the implicit  advantage to not have any kind of traditional 
- *    serialization for per-cpu data
- *    b. On uniprocessors, you don't want another kernel thread messing
- *    up with the same per-cpu data due to preemption
- *    
- * So, Use get_cpu_ptr to disable preemption and get pointer to the 
- * local cpu version of the per-cpu object. Use put_cpu_ptr to enable
- * preemption.  Operations on per-cpu data between get_ and put_ is
- * then considered to be safe. And ofcourse, "Thou shalt not sleep between 
- * get_cpu_ptr and put_cpu_ptr"
- */
-#define get_cpu_ptr(ptr) per_cpu_ptr(ptr, get_cpu())
-#define put_cpu_ptr(ptr) put_cpu()
-
#endif /* __LINUX_PERCPU_H */
diff -ruN linux-2.6.9-rc3-mm2-cln/mm/slab.c linux-2.6.9-rc3-mm2/mm/slab.c
--- linux-2.6.9-rc3-mm2-cln/mm/slab.c	2004-10-05 13:59:56.436888255 +0200
+++ linux-2.6.9-rc3-mm2/mm/slab.c	2004-10-05 13:58:44.000000000 +0200
@@ -2435,8 +2435,7 @@
/**
 * __alloc_percpu - allocate one copy of the object for every present
 * cpu in the system, zeroing them.
- * Objects should be dereferenced using per_cpu_ptr/get_cpu_ptr
- * macros only.
+ * Objects should be dereferenced using per_cpu_ptr macro only.
 *
 * @size: how many bytes of memory are required.
 * @align: the alignment, which can't be greater than SMP_CACHE_BYTES.


--
J.A. Magallon <jamagallon()able!es>     \               Software is like sex:
werewolf!able!es                         \         It's better when it's free
Mandrakelinux release 10.1 (Community) for i586
Linux 2.6.9-rc3-mm2 (gcc 3.4.1 (Mandrakelinux 10.1 3.4.1-4mdk)) #1


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